Nice find Paul. For some reason that spark-plug cap reminds me of those used on old CRT TV's for the high voltage connection.
@CNew needs to do some more homework , the letters forming part of the model number on these TAS/Tanaka engines gives the tool they were used on, e.g;
*BC= brush cutter
*CS= chain saw
*ED= engine drill
*EG= electric generator
*HT= hedge trimmer
*OB= outboard
The history page at "Hitachi/Metabo" indicates the T-23 engine was produced from 1975.
They are also still incorrectly claiming to have introduced the world smallest industrial two-stroke engine (P7) in 1962, how wrong they are.
https://www.metabo-hpt.com/us/main-navigation/tanaka-history
And they still can't spell Villiers.
David